Photonically partitioned continuous gas envelope and transiently energized pilot discharge areas used in address selection of display firing coordinates

ABSTRACT

Plural pilot cells in a gas panel envelope are energized selectively and transiently to effect partial control of firing coordinate selection. The pilot cells remain unenergized during normal sustaining periods and firing potentials are chosen to preclude sustaining discharge of pre-ignited unselected points so that pilot bias is produced exclusively by the pilot cell operations. The pilot cells and associated display coordinates receiving pilot bias therefrom are photonically isolated from each other by suitably spaced glass spacing rods. Since the pilot cells are only transiently energized less power is consumed and the pilot light emissions do not interfere with the apparently continuous light at the sustained display coordinates. Hence the pilot emissions need not be masked from view. Since the pilot lights have dual usage as a coordinate factor of firing selection other parameters of firing coordinate selection (i.e. voltages directly applied to the coordinates) and associated selection circuits may be simplified and reduced in size to effect cost and power economies.

United States Patent [191 Lamoureux lMarch 13, 1973 [75] Inventor: William Roger Lamoureux, Kingston, N.Y.

[73] Assignee: International Business Machines Corporation, Armonk, N.Y.

[22] Filed: Dec. 30, 1971 [211 App]. No; 214,126

[52] US. Cl ..340/166 R,3l3/l08 B,3l5/l69R [51] Int. Cl ..;..H0lj 1/00, HOlj 7/30 [58] Field of Search....340/166 R, 324 R; 313/108 B;

[56] References Cited UNITED STATES PATENTS 3,609,658 9/1971 Soltan ..34'0/l66 R Primary Ex ner-D n d Yus AttorneyW. N. Barret, Jr. et al.

x-v DISPLAY CONTROLS AND M 2 POWER SUPPLY 1 ABSTRACT Plural pilot cells in a gas panel envelope are energized selectively and transiently to effect partial control of firing coordinate selection. The pilot cells remain unenergized during normal sustaining periods and firing potentials are chosen to preclude sustaining discharge of pre-ignited unselected points so that pilot bias is produced exclusively by the pilot cell operations. The pilot cells and associated display coordinates receiving pilot bias therefrom are photonically isolated from each other by suitably spaced glass spacing rods. Since the pilot cells are only transiently energized less power is consumed and the pilot light emissions do not interfere with the apparently continuous light at the sustained display coordinates. Hence the pilot emissions need not be masked from view. Since the pilot lights have dual usage as a coordinate factor 8 Claims, 9 Drawing Figures PATENTEDMARIBIQB 3.720.919

' sum 20F 4 j FIG.4 I

I 7 FULL SUSTAIN WRITE SUSTAIN WRITE SUSTAIN 7 CYCLE I CELL VOLTAGE I 95 SHORT WAIT TIME MAY BE WRITE CANCEL NEEDED TO IMPROVE MARGINS LEAVES SUSTAIN I 1/2w 1/2w 55L sus sus XLINE NEW WRITE 35 CANCEL SEL I I I YLINE I mm P1 H I PILOT P11 I I I FIG.'6

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PATENTEDHAR 13 I915 3.720.919

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PHOTONICALLY PARTITIONED CONTINUOUS GAS ENVELOPE AND TRANSIENTLY ENERGIZED PILOT DISCHARGE AREAS USED IN ADDRESS SELECTION OF DISPLAY FIRING COORDINATES CROSS-REFERENCE TO RELATED APPLICATIONS BACKGROUND OF THE INVENTION 1. Field of the Invention The invention pertains to gas panel display devices and methods of operation thereof.

2. Description of the Prior Art The Soltan patent referenced above discloses gas panel display apparatus in which the gas envelope contains strategically situated pilot discharge areas or cells and associated pilot electrodes, the latter supplied with continuous (i.e. regular) electrical energization. The pilot cell discharges provide a virtually continuous flux of charged particles (metastables, electrons and ions) distributed uniformly throughout the indicating area of the envelope.

The supply of continuous energy to the pilot electrodes represents a power drain as well as a not insignificant factor in total power consumption of the system. Accordingly, one object of the invention is to reduce the power consumption of pilot cells in a gas display panel.

In regard to the just mentioned object I have found that the biasing metastable flux produced by the pilot cell achieves a stable steady state biasing condition suitable for controlling ignition of display coordinate sites very shortly after the pilot discharge begins. Consequently, by coordinating selective pilot cell operations with firing energization of display cells, while suppressing sustaining illumination from surrounding display cells, the pilot selection serves as a positive controlling factor in ignition (firing) operation.

I have also found that glass rods, which ordinarily are located at the envelope periphery and used as spacers to establish the height dimension of the gas envelope, may be located between pilot cells and when so situated provide effective photonic isolation between adjacent gas volumes on either side. Thus, an energized pilot cell in one partitioned volume section produces a metastable flux affecting display sites of only its respective section and not those of other partitioned volumes. This means that by selective energization of pilot cells in time coordination with application of firing potentialsto select display cell coordinates in multiple envelope sections selective ignition of a cell in the section having the active pilot may be achieved; the pilot selection thereby serving as a coordinate(addressing) factor in firing selection of display ignition points, as well as a source of metastables requisite to ignition generally.

Accordingly another object of the invention is to provide a gas panel with plural selectively ignitable and jointly sustainable sets of display coordinate point sites and with plural pilot cells providing both transient bias metastable conditioning of respective sets of display sites and selection control to control selective ignition of partially energized sites in respective sets.

The foregoing and other features, aspects and objectives of the present invention will be more fully appreciated by considering the following detailed description thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic top view of an exemplary form of the subject panel arrangement with associated signal control sources;

FIG. 1A illustrates an alternative pilot electrode arrangement;

FIGS. 2-6 are illustrative waveform diagrams illustrating the signal parameters for controlling selective ignition of display coordinates and unselective maintenance (sustaining) or erasure of pre-ignited coordinates;

FIGS. 7A and 78 comprise a schematic exemplification of the logic circuits required for producing the signal functions illustrated in FIGS. 2-6.

DETAILED DESCRIPTION FIG. 1 illustrates a gas display panel partitioned into two photonically isolated sections, in accordance with the invention, for selective initial ignition (firing) and unselective maintenance (sustaining) of display coordinate illumination effects. The extension to multiple relatively isolated sections and multiple wiring subgrids will be immediately apparent as the description proceeds.

Referring to FIG. 1 transparent (e.g. glass) flat memhers I and 3, comprising opposite front and near con taining faces of an ionizable gas envelope, have printed on respective interior surfaces orthogonal grids of insulatively coated X and Y conductors designated by 5 and 7. Conductor 9 connect individual conductors of grid 5 with respective sources X1-X4 of electrical control signal functions and conductors 11 provide similar connection between conductors 7 and Y control signal function Yl-Y4.

Transparent element 15, e.g. a thin glass rod, partitions the otherwise continuous gas envelope into discrete sections I and II. Although the gas volumes of these two sections are interconnected in the spaces between the ends of the glass rod 15 and the periphery of the sealing material which forms the lateral border of the envelope, I have found, nevertheless that the gas in each section is photonically isolated from the gas in the other section. This means that electrons, metastables and ions produced during display ignition and/or sustaining discharge in section I do not freely diffuse through section II, and conversely electrons, metastables and ions produced in section II do not enter sec? tion I in appreciable numbers.

Pilot electrodes 17 and 19, covering wider envelope areas than the individual thin conductors of grids 5 and 7, are incorporated in member I and span respective isolated pilot cell volumes of respective envelope sections I and II. A common counter electrode 21 incorporated in the printed circuitry of member 3 spans both pilot cell volumes. Pilot conductors 17 and 19 are connected to respective pilot signal outlets P1 and P2 of the control circuits 23 which also provide the display control signals Xl-X4 and Yl-Y4. Conductor 21 is connected to the common ground reference 27 of circuits 23.

Alternatively, as shown in FIG. 1A both the counter electrode 21 and electrodes 17 and 19 may be placed on member 1 allowing tight control of spacing since it is a function of artwork tolerance only. This allows closer gap spacing and shaping which is more conducive to causing an initial firing.

OPERATION OF THE INVENTION Those skilled in the subject arts will appreciate that intersections of the conductors in the X and Y grids 5 and 7 represent discretely ignitable indicating sites at which apparently continuous point area illumination effects may be produced by application of alternating current sustaining potentials of suitable amplitude and timing to the intersecting conductors. Coordinate sites which have been previously ignited, for instance by means described below, have locally confined metastable and electrical charge conditions within the adjacent gas envelope which are distinct from conditions present at other unfired or unignited coordinate sites. Hence, sustaining excitation applied unselectively to all intersecting conductors produces indication sustaining discharges only at previously ignited sites.

It is noted for subsequent discussion that the preignited sites discharge and emit light only intermittently during the rise and fall of the sustaining excitation; but the iteration rate of the sustaining excitation when properly selected provides flicker-free indication. During successive positive and negative phases of each sustaining cycle sustained sites discharge and charge rapidly to opposite metastable conditions distinct from unignited sites, photons being released only while the discharges are occurring. Thus sites would be unaffected by continued sustaining energization of the same polarity. This may be viewed as somewhat analagous to the charging and discharging of an ordinary capacitor by an alternating electric current exceeding the chargin g capacity of the capacitor in each half cycle.

The signal parameters for operating the panel structure shown in FIG. 1 are indicated in FIGS. 2-6. FIG. 2 indicates that firing the display cell site in section I associated with the intersection in that section of conductors connected to signal sources X and Y, is achieved by applying coincidental bias discharge energization V to line 21 via P, (FIG. 1) and partial increments V 2% W and 5% W of firing voltage (V W) to X; and Y respectively. Since the conductors carrying the signal functions X and Y, intersect at two display cells (in general n cells) in the arrangement of FIG. 1 (i.e. one point in section I and another in section II) both cell coordinates receive applied voltages of V W effective to fire the cells when and only when bias photonic conditions are present in the adjacent gas volume. I-Iowever effective photonic bias conditions are produced only during discharge operation of pilot cells or neighboring display cells and not by ambient or other conditions. It will be seen below that pilot cells are energized only while display cells other than cells selected for firing are in non-discharging state of operation. Therefore pilot cell operations effect selective control over display cell firing.

Sustaining operation is indicated in FIG. 3. Sustaining potentials are applied regularly in the indicated form to all X and Y coordinate selection conductors while pilot excitation sources P P remain idle. The resulting voltage appearing across each intersection coordinate of the display (i.e. at each display cell site) is the alternating potential indicated in the third row of FIG. 3; the amplitude V being chosen to be sufficient to produce momentary discharges in the envelope at previously ignited display cell sites regardless of pilot cell condition.

The relative timing and polarity of firing and sustaining voltage functions shown in FIG. 4 are quite important to the operation of the present invention and should be especially noted. It should be observed that firing increment W has the same polarity as the last preceding sustain pulse. It should berecalled from previous discussion that pre-ignited sustaining cells emit light only while discharging and charging to reverse polarity in reaction to reverse sustaining voltage pulses. Fully charged sustaining cells do not emit additional light when energized by pulses of the same polarity. Hence the firing pulses do not affect the photonic state of the sustaining cells, the latter being fully charged in the same polarity direction. Accordingly the photonic state of the gas in the vicinity of selected cells receiving the firing pulse V W will be governed exclusively by the state of energization of respective pilot cell conductor 17 or 19 since all other potentially effective metastable sources are idle at firing time.

Thus, the biasing effect of pilot source P, (FIG. 4) concurrent in time with the application of potential V W between display coordinate conductors X, Y, permits ignition of the display cell at coordinate X,, Y, in section I while the corresponding cell coordinate X Y, in unbiased section II, receiving the same selection voltage, maintains its previous condition (unignited or sustaining).

During the same writing interval unselected X lines receive less than the sustaining level of X voltage and the unselected Y lines may receive cancelling or deselect excitation of k W (see the second exemplary write cycle in FIG. 4) as a safety factor to assure that partially selected display cells in the envelope section containing the energized pilot have improved margins of operation. The net voltage across such partially selected cells is the sustaining voltage as indicated at, 95 in FIG. 4.

A preferred technique used to assure that the write excitation applied to the display coordinate has the same polarity and appropriate timing relative to the stable charging phase of the last received sustaining excitation is to follow the practice as indicated in FIG. 4 of having the write excitation coincide with the positive phase of one Sustain cycle while inhibiting the preceding negative Sustain cycle. When this is done it is advisable to require that successive Write (firing) cycles be separated by at least one full negative and positive sustain cycle in order to prevent loss of sustaining charge conditions in sustaining cells during long writing sequences. Alternatively the system could be programmed to interpose sustaining cycles after a predetermined number of successive writing cycles.

Another alternative to speed up writing functions would be to permit negative polarity writing following stable charge phase of negative Sustain cycles, with appropriate suppression of the last precedent positive Sustain cycle if required.

FIG. 6 indicates that if desired pilot sources P, and P may be simultaneously energized to fire display cells simultaneously at corresponding coordinates of both envelope sections I and II; for instance when, by computer calculation or the like, points of a display image being written upon the face of the panel have been grouped for such simultaneous firing selection.

FIG. 5 indicates that all sustaining display cells may be erased or restored to non-sustaining stable condition by application of plural short duration cycles of alternating current excitation to the intersecting conductors.

Although the particular circuitry required for producing pilot and display cell operating signals is not considered relevant or critical to the present invention a typical implementation is shown in the composite schematic of FIGS. 7A and 7B for the sake of completeness.

The X sustaining function (X/S) is transferred unconditionally via drive circuit 100 to center tap 101 of secondary winding 102 of transformer 103 establishing a floating level upon which Write pulses transferred via transistor gate 105 and primary winding 107 are differentially superimposed. The Y sustaining pulses, gated only when write pulse source is idle (Not Write Condition), are amplified by driver circuit 109 and fed as Y sustaining signal Y/S to center tap 111 of transformer secondary winding 1 13.

Output of secondary 102 is shunted across four identical switch circuits 115, 117, 119, 121 used to condition respective X lines X X X X Likewise output of secondary 103 is shunted by four identical Y switch circuits 123, 125, 127, 129.

Circuits 115, 117, 119 and 121 are conditioned by respective outputs of X-decoding circuits 131 and circuits 123, 125, 127 and 129 are conditioned by respective outputs of Y-decoding circuits 133.

Four bits A A A A of a five-bit binary address function (A A A A A.,) control the states of circuits 131 and 133. In the absence of Write energization the two ends of each secondary winding are at equal potentials and the X-lines (XI-X4) are all at a potential effectively determined by X/S and Y lines are at a potential determined by Y/S. When the Write pulse rises circuits 131 and 133 condition the switch circuits to produce firing potential (under pilot bias conditions) between a select one of the X lines Xl-X4 and a select Y line of the group Yl-Y4. The unselected X and Y lines receive degating potentials limiting the potentials across unselected cells to sustain potential.

Typical potential level useful for the purposes are sustaining pulse V 150 volts; Write increment W: i 40 volts.

Finally, address bit A controls selective connection of pilot potential V, to the pilot outlets P, and P Joint Pilot Select operates both gating paths to P,, P permitting simultaneous operation of both pilot conductors when appropriate for achieving parallel firing operations in sections I and II as characterized in FIG. 6.

We have shown and described above the fundamental novel features of the invention as applied to a preferred embodiment. It will be understood that various omissions, substitutions and changes in form and detail of the invention as described herein may be made by those skilled in the art without departing from the true spirit and scope of the invention. It is the intention therefore to be limited only by the scope of the following claims.

What is claimed is:

l. In a gas panel display system including a gas confining envelope which encompasses discrete display and pilot ignition areas, said display area including multiple selectively ignitable and jointly sustainable display cells electrically coupled in multiple to associated coordinate selection conductors, and said pilot area having at least one discrete pilot electrode conductor electrically coupled thereto, the improvement comprising:

first means for supplying partial ignition controlling pulse excitation on a transient basis coordinately to said pilot conductor and to select coordinate selection conductors to effect ignition at select display cells, the pulses applied to the coordinate selection conductors having predetermined polarity incapable of producing sustaining illumination discharges at previously fired but presently unselected display cells; and

second means for supplying unselective sustaining excitation on a regular repetitive basis to all coordinate selection conductors sufficient to maintain virtually continuous illumination at all previously ignited display points independently of the energization state of said pilot area. 2. In a gas panel system according to claim 1: third means operative jointly with said first means on said transient basis for supplying predetermined de-select (cancelling) pulse excitation on said transient basis to coordinate selection conductors associated with non-selected display cells.

3. In a gas panel system according to claim 1:

means partitioning said envelope into plural photonically isolated compartments having respective pilot areas and pilot conductors, and respective subsetsof display cells coupled in multiple to said coordinate selection conductors; said first means including means to energize said pilot conductors selectively to direct selective ignition of select display cells in the subsets of the respective compartments.

4. In a gas panel display including an envelope containing an ionizable gas and encompassing discrete pilot and display areas for producing pilot bias discharges and sustained display illumination point area discharges, the improvement comprising:

means subdividing said envelope into plural photonically isolated compartments and having individual pilot and display cell sub-areas;

means for coordinately energizing selected said pilot sub-areas and selected display cell coordinates in plural said display cell sub-areas including the display sub-area in the compartment containing the energized pilot sub-area with energy timed suitably for producing ignition only at the select display cell coordinates in the pilot energized compartment and unsuited for producing illumination by sustaining discharge of previously ignited coordinates.

5. In a gas panel display system including an envelope which contains an ionizable gas and encompasses relatively discrete pilot and display areas reserved for pilot bias conditioning and display indication and having means for coupling alternating current electrical energy simultaneously to multiple discrete display point areas within said display area sufficient in repetition frequency duration and amplitude to produce illumination sustaining discharges of alternating polarity at and only at previously ignited said display point areas, the improvement comprising:

first means for producing electrical ignition conditioning selection pulse signals having predetermined timing and amplitude in relation to said sustaining energy for effecting partial firing conditioning of select coordinate points during intervals between sustaining discharges; and

second means for producing bias photonic conditioning of said gas concurrent with operation of said first means as a selection controlling parameter to effect firing of particular said partially conditioned points.

6. In a gas panel display, in combination:

a continuous gas envelope partitioned into plural connected but photonically isolated compartments;

plural pilot conductors associated with respective said compartments for selectively establishing bias photonic conditions confined exclusively within bounds of respective compartments on a transient pulse basis; and

plural grids of orthogonal firing conductors intersecting in firing coordinate sub-matrices in plural said compartments for establishing sustaining, erasing and partial firing conditions at respective intersection coordinates in said compartments in multiple, whereby said coordinates are fired only when the respective compartments are in said bias photonic condition by operation of said pilot conductors coincident with establishment of said partial firing condition.

7. In a gas panel display, in combination:

means forming a continuous gas envelope partitioned into plural connected but photonically isolated compartments;

plural orthogonal sub-grids of conductors intersecting at sub-matrices of firing coordinates contained within bounds of respective said compartments;

plural pilot conductors associated exclusively with respective said compartments and positioned apart from the said firing coordinates of said compartments; and

means for selectively energizing said pilot conductors transiently and said coordinate conductors regularly in order to establish persistent point discharge firing conditions at firing coordinates in selected compartments associated with the pilot conductors.

8. In a gas panel display, in combination:

means forming a continuous gas envelope partitioned into plural connected but photonically isolated compartments; plural orthogonal sub-grids of conductors intersecting within bounds of respective said compartments to form submatrices of multiple firing contained wholly within bounds of respective said compartments;

means for supplying transient energization to selected said pilot conductors and multiple said grid conductors coincidentally to effect establishment of point discharge firing condition at select firing coordinates of only the compartments associated with the energized pilot conductors;

and means for supplying varying energization jointly to all of said grid conductors to effect either reinforcement or erasure of pre-established discharge conditions at firing coordinates throughout said envelope.

* II! I 

1. In a gas panel display system including a gas confining envelope which encompasses discrete display and pilot ignition areas, said display area including multiple selectively ignitable and jointly sustainable display cells electrically coupled in multiple to associated coordinate selection conductors, and said pilot area having at least one discrete pilot electrode conductor electrically coupled thereto, the improvement comprising: first means for supplying partial ignition controlling pulse excitation on a transient basis coordinately to said pilot conductor and to select coordinate selection conductors to effect ignition at select display cells, the pulses applied to the coordinate selection conductors having predetermined polarity incapable of producing sustaining illumination discharges at previously fired but presently unselected display cells; and second means for supplying unselective sustaining excitation on a regular repetitive basis to all coordinate selection conductors sufficient to maintain virtually continuous illumination at all previously ignited display points independently of the energization state of said pilot area.
 1. In a gas panel display system including a gas confining envelope which encompasses discrete display and pilot ignition areas, said display area including multiple selectively ignitable and jointly sustainable display cells electrically coupled in multiple to associated coordinate selection conductors, and said pilot area having at least one discrete pilot electrode conductor electrically coupled thereto, the improvement comprising: first means for supplying partial ignition controlling pulse excitation on a transient basis coordinately to said pilot conductor and to select coordinate selection conductors to effect ignition at select display cells, the pulses applied to the coordinate selection conductors having predetermined polarity incapable of producing sustaining illumination discharges at previously fired but presently unselected display cells; and second means for supplying unselective sustaining excitation on a regular repetitive basis to all coordinate selection conductors sufficient to maintain virtually continuous illumination at all previously ignited display points independently of the energization state of said pilot area.
 2. In a gas panel system according to claim 1: third means operative jointly with said first means on said transient basis for supplying predetermined de-select (cancelling) pulse excitation on said transient basis to coordinate selection conductors associated with non-selected display cells.
 3. In a gas panel system according to claim 1: means partitioning said envelope into plural photonically isolated compartments having respective pilot areas and pilot conductors, and respective subsets of display cells coupled in multiple to said coordinate selection conductors; said first means including means to energize said pilot conductors selectively to direct selective ignition of select display cells in the subsets of the respective compartments.
 4. In a gas panel display including an envelope containing an ionizable gas and encompassing discrete pilot and display areas for producing pilot bias discharges and sustained display illumination point area discharges, the improvement comprising: means subdividing said envelope into plural photonically isolated compartments and having individual pilot and display cell sub-areas; means for coordinately energizing selected said pilot sub-areas and selected display cell coordinates in plural said display cell sub-areas including the display sub-area in the compartment containing the energized pilot sub-area with energy timed suitably for producing ignition only at the select display cell coordinates in the pilot energized compartment and unsuited for producing illumination by sustaining discharge of previously ignited coordinates.
 5. In a gas panel display system including an envelope which contains an ionizable gas and encompasses relatively discrete pilot and display areas reserved for pilot bias conditioning and display indication and having means for coupling alternating current electrical energy simultaneously to multiple discrete display point areas within said display area sufficient in repetition frequency duration and amplitude to produce illumination sustaining discharges of alternating polarity at and only at previously ignited said display point areas, the improvement comprising: first means for producing electrical ignition conditioning selection pulse signals having predetermined timing and amplitude in relation to said sustaining energy for effecting partial firing conditioning of select coordinate points during intervals between sustaining discharges; and second means for producing bias photonic conditioning of said gas concurrent with operation of said first means as a selection controlling parameter to effect firing of particular said partially conditioned points.
 6. In a gas panel display, in combination: a continuous gas envelope partitioned into plural connected but photonically isolated compartments; plural pilot conductors associated with respective said compartments for selectively establishing bias photonic conditions confined exclusively within bounds of respective compartments on a transient pulse basis; and plural grids of orthogonal firing conductors intersecting in firing coordinate sub-matrices in plural said compartments for establishing sustaining, erasing and partial firing conditions at respective intersection coordinates in said compartments in multiple, whereby said coordinates are fired only when the respective compartments are in said bias photonic condition by operation of said pilot conductors coincident with establishment of said partial firing condition.
 7. In a gas panel display, in combination: means forming a continuous gas envelope partitioned into plural connected but photonically isolated compartments; plural orthogonal sub-grids of conductors intersecting at sub-matrices of firing coordinates contained within bounds of respective said compartments; plural pilot conductors associated exclusively with respective said compartments and positioned apart from the said firing coordinates of said compartmentS; and means for selectively energizing said pilot conductors transiently and said coordinate conductors regularly in order to establish persistent point discharge firing conditions at firing coordinates in selected compartments associated with the pilot conductors. 